標準號：BS EN 61158-5-17-2008
中文標準名稱：工業通訊網絡.現場總線規范.應用層設備定義.17型元件
英文標準名稱：Industrial communication networks — Fieldbus specifications — Part 5-17: Application layer service definition — Type 17 elements
標準類型：L79;M10
發布日期：2009/1/31 12:00:00
實施日期：2009/1/31 12:00:00
中國標準分類號：L79;M10
國際標準分類號：35.100.70;35.160;35.240.50
引用標準：IEC/TR 61158-1;ISO/IEC 7498;ISO/IEC 9545;ISO/IEC 10731
適用范圍：The fieldbus Application Layer (FAL) provides user programs with a means to access thefieldbus communication environment. In this respect, the FAL can be viewed as a “windowbetween corresponding application programs.”This standard provides common elements for basic time-critical and non-time-criticalmessaging communications between application programs in an automation environment andmaterial specific to Type 17 fieldbus. The term “time-critical” is used to represent thepresence of a time-window, within which one or more specified actions are required to becompleted with some defined level of certainty. Failure to complete specified actions withinthe time window risks failure of the applications requesting the actions, with attendant risk toequipment, plant and possibly human life.This standard defines in an abstract way the externally visible service provided by thedifferent Types of the fieldbus Application Layer in terms ofa) an abstract model for defining application resources (objects) capable of beingmanipulated by users via the use of the FAL service,b) the primitive actions and events of the service;c) the parameters associated with each primitive action and event, and the form which theytake; andd) the interrelationship between these actions and events, and their valid sequences.The purpose of this standard is to define the services provided to1) the FAL user at the boundary between the user and the Application Layer of the FieldbusReference Model, and2) Systems Management at the boundary between the Application Layer and SystemsManagement of the Fieldbus Reference Model.This standard specifies the structure and services of the IEC fieldbus Application Layer, inconformance with the OSI Basic Reference Model (ISO/IEC 7498) and the OSI ApplicationLayer Structure (ISO/IEC 9545).FAL services and protocols are provided by FAL application-entities (AE) contained within theapplication processes. The FAL AE is composed of a set of object-oriented ApplicationService Elements (ASEs) and a Layer Management Entity (LME) that manages the AE. TheASEs provide communication services that operate on a set of related application processobject (APO) classes. One of the FAL ASEs is a management ASE that provides a commonset of services for the management of the instances of FAL classes.Although these services specify, from the perspective of applications, how request andresponses are issued and delivered, they do not include a specification of what the requestingand responding applications are to do with them. That is, the behavioral aspects of theapplications are not specified; only a definition of what requests and responses they cansend/receive is specified. This permits greater flexibility to the FAL users in standardizingsuch object behavior. In addition to these services, some supporting services are also definedin this standard to provide access to the FAL to control certain aspects of its operation.